Why is acetic orcein stain used in mitosis experiment?
Hydrochloric acid will break down the pectins that hold the cell together. Acetic orcein will stain the chromosomes dark red and fix the cells, stopping mitosis. You should examine your preparation carefully for cells undergoing different stages of mitosis.
Why is toluidine blue used in mitosis?
Toluidine blue is used to stain the DNA in the meristem cells, rather than the usual acetic orcein, giving a simpler and less hazardous process for the students, and producing an excellent level of contrast within the cells.
What method can be used to investigate mitosis in onion garlic root tip?
Use a light microscope to observe, identify and draw root tip meristem cells in different stages of the cell cycle. measure the sizes of some of these cells. calculate the mitotic index for the garlic root tip tissue that they observe.
How does Aceto-orcein stain work?
Treatment with acid and heat is used to break up the cellulose cell wall allowing stain to permeate the tissue and makes it easier to squash the tissue on a microscope slide. Aceto-orcein stain turns chromosomes a purple-red colour.
How do you use Aceto-orcein stain?
Orcein is used in form of a 1% solution in 45% acetic acid. This solution is prepared by pouring 55 mL boiling glacial acetic acid over 1 g orcein powder. The solution is cooled, 45 mL of distilled water added, and filtered. This solution is unstable and should be prepared fresh before use.
What is acetic orcein?
Definition of aceto-orcein : a biological stain consisting of orcein in solution with acetic acid Root tips were obtained and stained with aceto-orcein, and root tip squashes were performed.—
How does Aceto-orcein interact with the chromosome?
Acetic acid fixation accommodates stretching of the chromosomes in the interband regions during a squash, thus providing for a higher resolution of the banding structure. The later addition of lactic acid to aceto-orcein (3) kept the glands softer in the fix and allowed for easier spreading of chromosomes.
How do you prepare a slide for mitosis?
An Alternative Procedure
- Cut the tip 5 to 8 mm from the tip of the freshly sprouted root.
- Place the cut tip on a clean microscope slide.
- Add 2-3 drops of acetocarmine stain to the slide.
- Warm the slide gently over the alcohol lamp for about one minute.
- Cover the slide with a cover slip or lens paper.
Why are the root tips immersed in acetic orcein stain?
Fixed root tips can be stored for at least two weeks prior to staining. Treatment with acid and heat is used to break up the cellulose cell wall allowing stain to permeate the tissue and makes it easier to squash the tissue on a microscope slide. Aceto-orcein stain turns chromosomes a purple-red colour.
How long does an onion root tip cell spend in mitosis?
about 80 minutes
TOTAL Number of Cells Remember that mitosis in an onion root tip normally takes about 80 minutes at room temperature. Calculate the amount of time each stage takes by mutiplying the percentage of cells in a stage by 80 minutes. Record your answers in the DATA TABLE.
Which time is appropriate to cut the root tips?
Onion root-tip cells have a cell cycle of approximately 24-hour duration, i.e., they divide once in 24 hours, and this division usually takes place about two hours after sunrise. Therefore, roots grown on water should be cut only at that time to score maximum number of dividing cells.